Countersinking device



Fig.2.

Fen/1607 (No Model.)

B. L. MANSFIELD.

GOUNTERSINKING DEVICE.

Patented Aug. 12, 1884.

it UNITED STATES PATENT Quince.

EDvVIN LASELLE MANSFIELD, OF BOSTON, MASSACHUSETTS.

COUNTERSINKING DEVlCE.

SPECIFICATION forming part of Letters Patent No. 303,303, dated August 12, 1884.

To all whom it may concern:

le-it known that I, EDWIN LASELL'E MAN-s FIELD, of Boston, in the county of Suffolk, of the Com mon wealth of Massachusetts, have in vented a new and useful Improvement in m plements for Boring'or Conntersinking; and I do hereby declare the same to be described in the following specification and represented in the accompanying drawings, ofm'hich Figure 1 is a side view, and Fig. 2 a longitudinal section, of a countersinking implement having my invention, the nature of which is defined in the claims hereinafter presented.

In such drawings, A. denotes a countersinking-bit having an angular; cutting end,a-. The shank b of such bit is screw-thrcadcd,as shown at c, to screw into and through a cylindrical nut, B, provided with a shoulder, d, as represented. This not has screwed intc'it transversely a check-screw, c, to bear against the 111g sleeve or tube, D, that encompasses the not B and the blade 1 of the bit, and is revoluble on the nut, and is held in place thereon by a screw, h, screwed into such sleeve, anda groove, '5, made within and encircling the nut. The sleeve is to determine the depth to which the bit is to enter a hole to be countersunk,

and such sleeve is adjustable relatively to the bit by the nut B, such nut, after having been revolved to effect any such adj nstment, being by the check-screw c kept from accidentally revolving on the shank of the bit. The bit (No model.)

ther into the hole, and by being forced against 5 the series of friction rollers or wheel the sleeve will be kept from being revolved with and by the bit and nut. W'cre the sleeve to bear di' rectly against the shoulder (Z of the nut, the said sleeve would be liable to be revolved with the-bit, and in so doing to mar or injure the surface adjacent to the countersink made by the bit. By having the ring and its series of frictiourollers arranged as represented, the sleeve, when its lesser end may be in contact 5 with the surface to be countersunk,will be at rest or not so revolved to injure or cut into such surface, though serving at the time to definethe depth of penetration of the bit. The sleeve is or may be provided with one or more chip-discharging openings, Z, made in it, as represented.

I claim 1. The combination of a boring or countersinking bit having its shank screw-threaded, 6

as described,and a screw-nut arranged on the screw of the shank, provided with a shoulder and a check-screw, as represented, with a sleeve encompassing the blade of the bit, and supported by and revoluble on the nut, as set 'forth.

2. The combination of a boring or countersinking bit having its shank screw-threaded, as described, and a screw-nut arranged on the screw of the shank, provided with a shoulder and check'screw, as represented, with asleeve encompassing the blade of the bit, and encircling and revoluble on the nut, and with a ring surrounding the nut, provided with a series of friction-rollers adapted to bear against 80 the shoulder of the nut and the larger end of the sleeve, all being substantially and to 0p crate as set forth.

EDWIN LASELLE MANSFIELD.

\Vi tn esses:

R. H. EDDY, E. B. PRATT. 

